Recommend Products
Name: Fujian Monel 400 Double End Stud Material: Monel 400 Standard: ASME B18.2.1 Size: 5/16 to 4 inch Length: 30 to 1000 mm Class: 12.9 Feature: Resistant to hydrofluoric acidQS Fastener: Monel 400 Double End Stud
Name: Inconel 625 Double End Stud Material: Inconel 625 Standard: ASME B18.2.1 Size: 5/16 to 4 inch Length: 30 to 1000 mm Class: 12.9 Feature: High Yield Strength, Durable Strength and Corrosion ResistanceQS Fastener: Inconel 625 Double End Stud
Name: Xiamen Inconel 600 High Strength Fastener Material: Inconel 600 Standard: ASME Size: 5/16 to 4 inch Length: 30 to 1000 mm Class: 12.9 Feature: High Yield Strength, Durable Strength and Corrosion ResistanceQS Fastener: Inconel 600 High Strength Fastener
Name: Inconel 600 Stud Bolt Putian Material: Inconel 600 Standard: ASME B18.2.1 Size: 5/16 to 4 inch Length: 30 to 1000 mm Class: 12.9 Feature: High Yield Strength, Durable Strength and Corrosion ResistanceQS Fastener: Inconel 600 Stud Bolt
1.7225 B7 Double End Stud
QS Fastener: 1.7225 B7 Double End Stud
Name: 1.7225 B7 Double End Stud
Standard: ASTM
Material: A193 B7
Size: 3/4 inch
Lenght: 100 mm
Surface: Black/ PTFE/ Zinc
Standard: ASTM
Material: A193 B7
Size: 3/4 inch
Lenght: 100 mm
Surface: Black/ PTFE/ Zinc
Quantity
1.7225 B7 Double End Stud
Manufactured from Cr-Mo alloy steel A193 B7 and meeting ASTM high-strength requirements, this part combines 3/4-inch threads with a 100 mm plain double-ended shank. Tensile strength is ≥ 860 MPa and service temperature up to 500 °C, making it ideal for valves, pressure vessels and oil-field equipment. Surface options include black oxide, PTFE coating or eco-friendly zinc, all passing 1 000 h salt-spray tests. EN 10204 3.1 third-party certification is supplied as standard. Full-size lots ship within 72 h and special requirements—left-hand thread, metric/UNC, cut-to-length stubs—can be customised to help projects pass inspection faster and cut total assembly cost.
Manufactured from Cr-Mo alloy steel A193 B7 and meeting ASTM high-strength requirements, this part combines 3/4-inch threads with a 100 mm plain double-ended shank. Tensile strength is ≥ 860 MPa and service temperature up to 500 °C, making it ideal for valves, pressure vessels and oil-field equipment. Surface options include black oxide, PTFE coating or eco-friendly zinc, all passing 1 000 h salt-spray tests. EN 10204 3.1 third-party certification is supplied as standard. Full-size lots ship within 72 h and special requirements—left-hand thread, metric/UNC, cut-to-length stubs—can be customised to help projects pass inspection faster and cut total assembly cost.
What is a B7 bolt actually for?
A B7 bolt is not the common “iron screw” seen on ordinary building sites; it is a high-strength Cr-Mo fastener produced to ASTM A193. Its chemistry is equivalent to China’s 42CrMoA and to AISI 4140/4142 in the United States. Taking 1.7225 B7 Double End Stud as an example, the material must be quenched and tempered (re-tempered at ≥ 593 °C), giving a typical tensile strength above 860 MPa and a room-temperature hardness ≤ 35 HRC while still retaining good impact toughness. Because it keeps its mechanical properties at high temperature (up to 500 °C) and high pressure, petroleum, chemical, power-generation and offshore industries treat it as a “critical-connection” component. The following real cases show exactly what it “does”.
A B7 bolt is not the common “iron screw” seen on ordinary building sites; it is a high-strength Cr-Mo fastener produced to ASTM A193. Its chemistry is equivalent to China’s 42CrMoA and to AISI 4140/4142 in the United States. Taking 1.7225 B7 Double End Stud as an example, the material must be quenched and tempered (re-tempered at ≥ 593 °C), giving a typical tensile strength above 860 MPa and a room-temperature hardness ≤ 35 HRC while still retaining good impact toughness. Because it keeps its mechanical properties at high temperature (up to 500 °C) and high pressure, petroleum, chemical, power-generation and offshore industries treat it as a “critical-connection” component. The following real cases show exactly what it “does”.
1. Refinery hydro-treating reactor
Operating pressure 10–20 MPa, temperature ~400 °C, highly penetrating hydrogen atmosphere. If ordinary 8.8 grade bolts are used on the head-to-shell flange they relax under sustained heat, causing leaks or even fire. After switching to 1.7225 B7 Double End Stud the yield strength at 450 °C is still above 600 MPa; used with A194-2H nuts and a graphite spiral-wound gasket the unit has run four years without a shutdown.
Operating pressure 10–20 MPa, temperature ~400 °C, highly penetrating hydrogen atmosphere. If ordinary 8.8 grade bolts are used on the head-to-shell flange they relax under sustained heat, causing leaks or even fire. After switching to 1.7225 B7 Double End Stud the yield strength at 450 °C is still above 600 MPa; used with A194-2H nuts and a graphite spiral-wound gasket the unit has run four years without a shutdown.
2. Power-plant main steam valve
Super-critical units: steam 540 °C/24 MPa. The valve bonnet is secured with 2″-8UN large-diameter 1.7225 B7 Double End Stud, each pre-loaded to 120 kN. One start-stop cycle produces a 500 °C temperature swing; the Cr-Mo microstructure resists thermal fatigue and prevents “necking” failure, allowing daily peak-load cycling in safety.
Super-critical units: steam 540 °C/24 MPa. The valve bonnet is secured with 2″-8UN large-diameter 1.7225 B7 Double End Stud, each pre-loaded to 120 kN. One start-stop cycle produces a 500 °C temperature swing; the Cr-Mo microstructure resists thermal fatigue and prevents “necking” failure, allowing daily peak-load cycling in safety.
3. Offshore platform riser clamp
Marine environment: high salt-spray, heavy seas, riser vibration 1–3 Hz. With PTFE-coated 1.7225 B7 Double End Stud, 1 000 h salt-spray test shows no red rust; fatigue strength is 30 % higher than carbon-steel bolts, resisting alternating loads and cutting diver interventions—one dive costs tens of thousands of dollars, so B7 slashes life-cycle expense.
Marine environment: high salt-spray, heavy seas, riser vibration 1–3 Hz. With PTFE-coated 1.7225 B7 Double End Stud, 1 000 h salt-spray test shows no red rust; fatigue strength is 30 % higher than carbon-steel bolts, resisting alternating loads and cutting diver interventions—one dive costs tens of thousands of dollars, so B7 slashes life-cycle expense.
4. Chemical heat-exchanger tube bundle
¾″ 1.7225 B7 Double End Stud fastens the U-tubes to the tube-sheet: tube side 320 °C hot oil, shell side cooling water. Should a bolt rust and break the bundle must be pulled, halting production and costing millions. B7 contains 1 % Cr, 0.2 % Mo, giving better corrosion resistance than plain steel; combined with galvanising or flame-sprayed aluminium it survives wet H₂S service for more than eight years.
¾″ 1.7225 B7 Double End Stud fastens the U-tubes to the tube-sheet: tube side 320 °C hot oil, shell side cooling water. Should a bolt rust and break the bundle must be pulled, halting production and costing millions. B7 contains 1 % Cr, 0.2 % Mo, giving better corrosion resistance than plain steel; combined with galvanising or flame-sprayed aluminium it survives wet H₂S service for more than eight years.
5. LNG liquefaction low-temperature pump
Although B7 is famous for high temperature, its impact value at –46 °C is still ≥ 47 J, so 1.7225 B7 Double End Stud is widely used on pump-discharge flanges inside LNG tanks. During start-up the liquid-hammer peak reaches 8 MPa; the high yield strength prevents instantaneous tensile failure and avoids cryogenic leaks that could freeze personnel.
Although B7 is famous for high temperature, its impact value at –46 °C is still ≥ 47 J, so 1.7225 B7 Double End Stud is widely used on pump-discharge flanges inside LNG tanks. During start-up the liquid-hammer peak reaches 8 MPa; the high yield strength prevents instantaneous tensile failure and avoids cryogenic leaks that could freeze personnel.
Summary
The core mission of 1.7225 B7 Double End Stud is to deliver a predictable, reproducible, high-strength connection under the fourfold punishment of high temperature, high pressure, vibration and corrosion. Replace it with an ordinary bolt and the result may be a leak—or an explosion; specify B7 correctly and you put a “seat-belt” on reactors, turbines and offshore platforms, allowing them to run safely, stably and economically for the long term.
The core mission of 1.7225 B7 Double End Stud is to deliver a predictable, reproducible, high-strength connection under the fourfold punishment of high temperature, high pressure, vibration and corrosion. Replace it with an ordinary bolt and the result may be a leak—or an explosion; specify B7 correctly and you put a “seat-belt” on reactors, turbines and offshore platforms, allowing them to run safely, stably and economically for the long term.
Send Message
